Ink Plus is a permanent keeper. The Ink Cash downgrade has a 25K annual 5X category limit. The Plus is double that. You won't get an annual fee with the Plus if you have any retention skills at all.
The Citi Premier and Prestige are pretty remarkable and if you're AA friendly, they can't really be argued against.
SPG is your call. I get a lot of value out of it, but Marriott looms.
I'm signing off on your proposed consolidated strategy. The only place you lose out is biz dining. Assess what that means to you.